Aye Win7 does perform pretty good, especially considering it's current non-released state.
There is an interesting article in this months PC Format magazine comparing gaming performance (with major titles along with the usual 3dmark stuff) for Xp, Vista and Win7. Both 32 bit and 64 bit iterations were used too. In summary, Win7 was the slowest (hey it's beta still) followed by Xp and then Vista (fastest).
The main thing with Vista is ram, and I'd not recommend anything less than 4gb. Give it room to breathe, turn off indexing and superfetch and it's pretty good. The current Win7 rc1 expires in the middle of 2010, which makes me wonder when it's going to release? :|
Rakku